taxonID	type	description	language	source
03C40E02FFFD5945E2BB685E180DB494.taxon	materials_examined	Type locality. Cherrapunji, Meghalaya state, India; Types. ZSIC, W 703 / 1. Material examined: none.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFD5945E2BB685E180DB494.taxon	description	Brief description (after Stephenson, 1923; Gates 1972) Length 50 – 110 mm, width 2 – 2.5 mm. Segments 116 – 188. First dorsal pore at 10 / 11 or 11 / 12. Prostomium epilobous, tongue open. Setae perichaetine. Clitellum annular, 12 / 13 – 16 / 17. Spermathecal pores two pairs 6 / 7 and 7 / 8 at b setal line. Male pores minute, on segment 17 at b setal line, near anterior or posterior end of seminal grooves. Septa 7 / 8 – 13 / 14 slightly thickened. Gizzard barrel shaped in segment 6. Intestine begins in segment 14. Typhlosole simple, lamelliform in segments 14 – 84. Calciferous glands stalked, 3 pairs in 10 – 12. Nephridia meroic. Last pairs of hearts in segment 12. Testes and funnels free in segment 9 and 10, seminal vesicles in segments 8 and 11. Prostates in segments 17 and 18, duct short, muscular, looped. Ovaries in segment 12. Spermathecae a small sac, sessile, diverticulum club shaped, about as long as ampulla. Penial setae absent.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFD5945E2BB685E180DB494.taxon	distribution	Distribution in India. Meghalaya: below Dumpep Dak bunglow, Dumpep, Cherrapunji, Jowai – Jaintia Hills, Mawphlang, Nongkhnum-Lailad, Shillong, Thadlaskien (Stephenson 1922; Gates 1934, 1945, 1972; Julka 1977; Bhadauria & Ramakrishnan 1989; Halder 1999 b; Kharkongor 2018); West Bengal: Toofanganj (Halder 1999 a).	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFD5941E2BB6A7D18E6B373.taxon	description	Brief description (after Gates, 1933, 1972) Setae lumbricine or perichaetine. Clitellum annular, on segments 12 – 16. Male pores on segment 17, with seminal grooves extending onto following segment. Female pores on segment 13. Spermathecal pores on segments 6 / 7 – 7 / 8. Gizzard large, cylindrical in segment 6. Intestine origin in segment 14. Nephridia meroic, clustered nephridia anterior to gizzard, exonephric micro-nephridia in segment 4 and posterior, enteronephric mega-nephridia along with micro-nephridia in the posterior segments only. Paired and stalked calciferous glands spanning in segments 9 – 12. Last pair of hearts in segment 12. Prostatic glands racemose and strap-shaped, testes and funnels in segments 9 and 10, seminal vesicles two to three pairs in segments 8 – 12. Ovaries and funnels in segment 12. Penial setae absent.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFE5945E2BB6D911D9AB07B.taxon	materials_examined	Type locality. Siki, Arunachal Pradesh; Types. ZSI, HARC, Solan, ZSI-HARC-An 110 to An 116 (Julka 1981). Material examined: none.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFE5945E2BB6D911D9AB07B.taxon	description	Brief Description (after Julka 1981) Length 162 – 207 mm, width 4 – 5 mm. Segments 176 – 383. Prostomium prolobous or pro-epilobous. First dorsal pore in intersegmental furrow 10 / 11 or 11 / 12. Setae lumbricine, setal formula aa = 1.43 – 1.83 ab = 0.75 – 0. 92 bc = 1.10 – 1.12 cd = 0.11 – 0.15 dd (before clitellum) and aa = 2.25 – 2.60 ab = 1.13 – 1.62 bc = 1.50 – 1.86 cd = 0.12 – 0.15 dd (postclitellar segments). Clitellum annular, on segments 13 – 15, setae present, dorsal pores absent. Spermathecal pores two pairs in 6 / 7 and 7 / 8 at a setal line. Male genital region extends across post setal of segment 16 and presetal of segment 18. Male pores in segment 17 at ab or b setal line, connected with deep transverse depression. Seminal grooves straight, with bent at both the ends, nearly E shaped. Female pores paired, minute, slight median to a line on segment 13. Septa 6 / 7 – 10 / 11 thickly muscular. Gizzard large in segment 6. Intestine begins in segment 14, typhlosole lamelliform, begin in segment 14 and end in segments 95 – 100. Calciferous glands stalked, three pairs in segments 10 – 12. Nephridia meroic, clustered nephridia associated with 5 / 6, exonephric micro-nephridia from segment 4 and posterior, enteronephric mega-nephridia in posterior segments only. Dorsal blood vessel single, extending anteriorly to the region of brain. Last pairs of hearts in segment 12. Testes and funnels in segments 9 and 10, iridescent; seminal vesicles three pairs in segments 8, 9 and 12. Prostate glands strap shaped, in segment 16 – 20, duct short, bent near ental end and narrow toward ectal end. Spermathecal ampulla spherical or sausage shaped; duct half as long as ampulla; diverticulum club shaped, little short or as long as combined length of ampulla and duct.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFE5945E2BB6D911D9AB07B.taxon	distribution	Distribution in India. Arunachal Pradesh: Ayumuring, Doginalo, Lemking, Seiom, Siki, Taliha (Julka et al. 1981).	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFE5944E2BB69FC1EE3B494.taxon	materials_examined	Type locality. Kabak, Arunachal Pradesh; Types. ZSI-HARC-An 117, ZSI-HARC-An 118. Material examined: none.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFE5944E2BB69FC1EE3B494.taxon	description	Brief description (after Julka 1981) Length 175 – 210 mm, width 4 – 5 mm. Segments 304 – 419. Prostomium pro-epilobous. First dorsal pore in 9 / 10. Setae perichaetine, present on segment 2. Clitellum is annular, on segments 13 – 16, setae present, dorsal pores absent. Spermathecal pores two pairs in 6 / 7 and 7 / 8 at a setal line. Male genital region extends across 17 and anterior of segment 18, seminal grooves begin in segment 17 in b line and end at 17 / 18 in line with c. Male pores minute in segment 17, equatorial, 0.09 circumference apart. Female pores paired, minute, just anterior and median to a setal line. Septa 6 / 7 – 10 / 11 strongly muscular. Gizzard large in segment 6. Intestine begin segment 14, typhlosole simple, lamelliform, begin in segment 14 and ending in front of 90 – 95. Calciferous glands stalked, 5 pairs, in segments 8 – 12. Nephridia meroic, clustered nephridia near 5 / 6, v shaped exonephric micro nephridia in segment 4 and posteriorly, enteronephric meganephridia in posterior segments only. Dorsal blood vessel complete continue anterior to the brain, last pairs of hearts in segment 12. Testes and funnels in segment 9 and 10, seminal vesicles in segment 10 and 11. Prostate glands strap shaped, in segments 17 – 18, duct muscular, bent at its ental end and slightly thickened toward ectal end. Spermathecal ampulla rounded and flattened; duct straight, narrow toward ectal end, about half as long as ampulla; diverticulum short, club shaped, at ental end of duct.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFE5944E2BB69FC1EE3B494.taxon	distribution	Distribution in India. Arunachal Pradesh: Kabak (Julka, 1981).	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFF5944E2BB6D9119AFB09F.taxon	materials_examined	Type locality. Lava, Neora Valley National Park, West Bengal, India; Types. ZSI-GNC-An 2203 / 1, ZSI-GNC- An 2204 / 1. Material examined: none.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFF5944E2BB6D9119AFB09F.taxon	description	Brief description (after Ahmed and Julka, 2022) Length 80 – 145 mm, width 4 – 6.5 mm. Segments 102 – 266. Prostomium prolobous. Setae lumbricine. Spermathecal pores one pair in intersegmental furrow 7 / 8 slight median to a setal line. The first dorsal pore in the intersegmental furrow 9 / 10. Clitellum annular, extends on the posterior half of segment 12 to the anterior half of segment 16, dorsal pores and setae present. Female pores minute, paired, and median and slight anterior to a setal line on segment 13. Male pores on segment 17 at ab, close to the b setal lines. The male genital shield spans across segment 17 and the anterior part of segment 18. Septa 6 / 7 – 10 / 11 thickened, and 11 / 12 slightly thickened. Gizzard large, cylindrical, in segment 6. Intestine begins in segment 14, with a lamelliform typhlosole possessing numerous closely set transverse folds along each side, starting from segment 14, reducing posteriorly, and ending in segment 99. Calciferous glands kidney-shaped, five pairs in segments 8 – 12, each gland partially encircled by the hearts of the corresponding segment. Nephridia are meroic, with clustered micro-nephridia present on the anterior face of the septa of segment 5 / 6, and enteronephric mega-nephridia along with micro-nephridia present only in posterior segments. Last pair of hearts in segment 12. Dorsal blood vessel passes through the gizzard into the pharynx. Testes and funnels in segments 9 and 10, seminal vesicles in segments 10 and 11. Prostates long, strap-shaped, extending in segments 17 – 26, with prostatic ducts emerging from the anterior end and looping forward before entering into the parietes in segment 17. Ovaries and funnels in segment 12. Spermathecae in segment 7, ampulla ovoid, duct about half as long as ampulla; diverticulum digitiform about the length of spermathecal duct.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFF5944E2BB6D9119AFB09F.taxon	distribution	Distribution in India. West Bengal: Lava, Neora Valley National Park (Ahmed et al. 2022).	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFF5943E2BB69981C08B4B8.taxon	materials_examined	Type locality. Wakro, Arunachal Pradesh, India; Types. ZSIC-An 112 / 1 – ZSIC-An 114 / 1 (Julka 1976). Material examined: none.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFF5943E2BB69981C08B4B8.taxon	description	Brief Description (after Julka 1976) Length, 158 – 390 mm, width 3 – 8 mm. Segments 280 – 390, segments 5 biannulate, 6 – 12 triannulate. Prostomium pro-epilobous. First dorsal pore, in intersegmental furrow 10 / 11. Setae, lumbricine, begin in segment 2; setal formula ab <cd <bc <aa. Clitellum 13 – ⅔ 16, setae present, dorsal pores occluded. Male genital shield extends across segment 17 and the posterior part of segment 16. Male pores large, on segment 17, at ab setal line. Seminal grooves straight, deep. Spermathecal pores two pairs in 6 / 7 and 7 / 8, slight median to a setal line. Septa, 6 / 7 – 9 / 10 thickened, 10 / 11 – 11 / 12, slightly thickened. Gizzard, elongated in segment 6. Intestinal origin in segment 14, typhlosole lamelliform, extends across 15 – 277, 296. Calciferous glands 4 pairs in segments 9 – 12. Nephridia meroic, cluster micro-nephridia in segment 6, enteronephric mega-nephridia along with exonephric micro-nephridia in posterior segments. Dorsal blood vessel continued anteriorly onto pharyngeal bulb. Last pairs of hearts in segment 12. Testes and funnels in segments 9 and 10, seminal vesicles in segments 10 and 11. Prostates strap shaped, extending across segments 16 – 18, prostatic duct looped near its origin, white, muscular, with a little shine. Spermathecal ampulla rounded, duct narrow toward ectal end, duct three times as long as ampulla; diverticulum club shaped, smaller than ampulla.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFFF5943E2BB69981C08B4B8.taxon	distribution	Distribution in India. Arunachal Pradesh: Hornbill, Tihun, Wakro, Zero camp 28 km NE of Miao (Julka 1976; Halder et al. 2007).	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFF85943E2BB6DAA1CB6B1EB.taxon	materials_examined	Type locality. Darjiling (Darjeeling) to Soom (Ghoom), West Bengal, India; Types. ZSIC 6525, BMNH 1933: 5: 25: 84 - 5 (Narayanan et al. 2023). Material examined: 7 aclitellate, 4 clitellate and one tail part, ZSI-GNC-An 6825 / 1; Thamsing mixed forest (27.001902 ° N; 88.170583 ° E), Sukiapokhri, Darjeeling, West Bengal, India; elevation 2130 m asl; 11.05.2022; collector Md. Nurul Hasan.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFF85943E2BB6DAA1CB6B1EB.taxon	description	Description. Length 130 – 225 mm, width 5 – 10 mm. Segments 210 – 302. Colour unpigmented. Prostomium pro-epilobous. Setae lumbricine, present on segment 2, setal formula aa = 1.5, ab = 1, bc = 3, cd = 1.5, dd = 1 / 2 circumference at segment 10. First dorsal pore in 9 / 10. Clitellum annular, slightly developed 13 – ½ 16, setae and dorsal pores present. Male genital region extends across segment 17 and half of segment 18, seminal grooves begin at b on segment 17 ends at segment 18 near setae c. Male pores on anterior end of seminal grooves on segment 17 at ab close to b setal line. Spermathecal pores 6 / 7 and 7 / 8 at or slightly median to a setal line. Female pores paired, just anterior and median to aa. Septa 6 / 7 – 9 / 10 thickened, 5 / 6 and 10 / 11 – 12 / 13 slightly thickened. Gizzard large, cylindrical in segment 6. Intestine begins in segment 14. Typhlosole simple, lamelliform, begin with intestine in segment 14 and ends before 135 – 142. Calciferous glands stalked, kidney shaped, five pairs, in segment 8 – 12. Nephridia meroic, clustered nephridia in segment 5 associated with 5 / 6, exonephric micro nephridia from segment 4 and posterior; enteronephric along with exonephric nephridia in posterior segments only. Dorsal blood vessel single end anterior in the region of brain. Last pairs of hearts in segment 12. Ovaries and funnels in segment 12. Testes and funnels free in segments 9 and 10. Seminal vesicles in 10, 11 and 12, vesicles of segment 10 larger than 11 and 12. Prostate glands strap shaped extends across 17 – 19,20, duct looped; paired vas deferens open separately near the ental end of prostatic duct. Spermathecae in segment 7 and 8, ampulla ovoid, duct wide, equal to or longer than ampulla. Diverticulum digitiform, ¾ length of duct and ampulla attached on anterior face at or slight below the middle of spermathecal duct.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFF85943E2BB6DAA1CB6B1EB.taxon	discussion	Remarks. In the original description, maximum width of species is 5 mm (immature specimens) (Stephenson, 1916), present study it ranges from 5 – 10 mm. Seminal vesicles are three pairs as in original description 10,11,12 instead of Gates 1972 two pairs in segments 10,11. Spermathecal diverticulum arises below the middle of duct, rather than base of ampulla. Prostate glands extend in two to three segments instead confined in segment 19. Further many associated nematodes were recorded in testes segment 10.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFF85943E2BB6DAA1CB6B1EB.taxon	distribution	Distribution in India. West Bengal: Darjeeling to Soom (Stephenson, 1916), Thamsing mixed forest (present study). Habitat: Soil in forest.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFF95942E2BB6CBA1E7FB0C2.taxon	materials_examined	Type locality. Janakmukh, Arunachal Pradesh, India; Types. ZSIC, ZEV 5159 / 7. Material examined: none.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFF95942E2BB6CBA1E7FB0C2.taxon	description	Brief description (after Gates 1972) Length 105 – 185 mm, width 5 – 6 mm. Segments 230 – 244. Setae lumbricine. First dorsal pore in intersegmental furrow 10 / 11. Clitellum annular, extending on segments 13 – 16, dorsal pores absent, setae present. Prostomium prolobous. Spermathecal pores two pairs 6 / 7 and 7 / 8 and at a setal line. Female pores paired in setal zone, on segment 13, median to aa. Male pores on segment 17 at b setal line. Septa 6 / 7 – 10 / 11 thickened. Gizzard in segment 6. Intestine begins in segment 14. Calciferous glands 4 pairs in segments 9 – 12. Nephridia meroic, tuft nephridia on anterior face of 5 / 6, mega-nephridia along with micro-nephridia in posterior segments only. Last pairs of hearts in segment 12. Ovaries and funnels in segment 12. Testes and funnels in segments 9 and 10; seminal vesicles in segment 10 and 11. Prostates in segments 17 – 20, strap shaped. Spermathecal duct larger than ampulla, diverticulum club shaped.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFF95942E2BB6CBA1E7FB0C2.taxon	distribution	Distribution in India. Arunachal Pradesh: Chikrung, Janakmukh (Stephenson 1914, 1923; Gates 1934, 1936, 1972; Julka 1976); Elsewhere. Myanmar (Gates 1972).	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFF95941E2BB68631E93B528.taxon	materials_examined	Type locality. Rotung (Rottung), Arunachal Pradesh, India; Types. ZSIC, ZEV 5410 / 7, ZEV 5384 / 7, ZEV 5386 / 7. Material examined: none.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFF95941E2BB68631E93B528.taxon	description	Brief description (after Gates 1972). Length 82 – 226 mm, width 3 – 6 mm. Segments 103 – 297. Prostomium prolobous, tongue open. First dorsal pore in 9 / 10. Setae lumbricine. Clitellum annular, on segments 13 – 15, setae present, dorsal pores absent. Spermathecal pores in 6 / 7 and 7 / 8 median to a setal line. Male genital shield thickened, marked by short transverse furrows, a pair of longitudinal seminal grooves, extending between 16 / 17 and 17 / 18. Male pores large, in seminal grooves, on segment 17, at a setal line. Female pores minute, paired, median to setae a on segment 13. Septa 6 / 7 – 8 / 9 strongly muscular, 9 / l 0 – 11 / 12 slightly muscular. Gizzard large, in segment 6. Intestine begin in segment 14. Typhlosole simple, lamelliform begin in segment 14 end in segment 90 – 95. Calciferous glands stalked, four pairs in segments 9 – 12. Nephridia meroic, clustered nephridia attached with 5 / 6, exonephric micro-nephridia in segment 4 and posterior, enteronephric mega-nephridia in posterior segments. Last pairs of hearts in segment 12. Testes and funnels in segments 9 and 10, seminal vesicles in segment 10 and 11. Prostates strap shaped in segments 17 – 19, duct short, U shaped. Spermathecal ampulla pear shaped, duct short confined to parietes; diverticulum club shaped, about as long as ampulla and duct. Ovaries and funnels in segment 12.	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
03C40E02FFF95941E2BB68631E93B528.taxon	distribution	Distribution in India. Arunachal Pradesh: 3 km east of Richik, Ayumuring, Damin, Gimba, Huri, Kabak, near Kau Pass, near Zoo staff quarters — Itanagar, Pabin, Parsipala, Renging, Richik, Rotung, Rui, Tali, Taliha, Tumbia, Upper Rotung, Yame (Stephenson 1914, 1923; Gates 1934, 1972; Julka 1981; Halder et al. 2007); Meghalaya: Near Puiñsneiñstream - Mawthar village, Nongstoiñ- Siejlieh (Kharkongor 2018).	en	Hasan, Md. Nurul, Reynolds, John Warren, Ahmed, Shakoor, Ghosh, Shyamasree, Mandal, Chandra Kanta, Kosygin, Laishram (2026): Redescription of earthworm species Tonoscolex monorchis (Stephenson, 1916) (Clitellata: Megascolecidae) from Darjeeling, India-A significant contribution after a quarter of a century. Zootaxa 5752 (2): 285-294, DOI: 10.11646/zootaxa.5752.2.7, URL: https://doi.org/10.11646/zootaxa.5752.2.7
